<?php

/*
 * This file is part of SwiftMailer. (c) 2004-2009 Chris Corbyn For the full copyright and license information, please view the LICENSE file that was distributed with this source code.
 */

/**
 * Analyzes US-ASCII characters.
 * 
 * @package Swift
 * @subpackage Encoder
 * @author Chris Corbyn
 */
class Swift_CharacterReader_UsAsciiReader implements Swift_CharacterReader {
	/**
	 * Returns the complete charactermap
	 *
	 * @param string $string        	
	 * @param int $startOffset        	
	 * @param string $ignoredChars        	
	 */
	public function getCharPositions($string, $startOffset, &$currentMap, &$ignoredChars) {
		$strlen = strlen ( $string );
		$ignoredChars = '';
		for($i = 0; $i < $strlen; ++ $i) {
			if ($string [$i] > "\x07F") { // Invalid char
				$currentMap [$i + $startOffset] = $string [$i];
			}
		}
		
		return $strlen;
	}
	
	/**
	 * Returns mapType
	 * 
	 * @return int mapType
	 */
	public function getMapType() {
		return self::MAP_TYPE_INVALID;
	}
	
	/**
	 * Returns an integer which specifies how many more bytes to read.
	 * A positive integer indicates the number of more bytes to fetch before invoking
	 * this method again.
	 * A value of zero means this is already a valid character.
	 * A value of -1 means this cannot possibly be a valid character.
	 * 
	 * @param string $bytes        	
	 * @return int
	 */
	public function validateByteSequence($bytes, $size) {
		$byte = reset ( $bytes );
		if (1 == count ( $bytes ) && $byte >= 0x00 && $byte <= 0x7F) {
			return 0;
		} else {
			return - 1;
		}
	}
	
	/**
	 * Returns the number of bytes which should be read to start each character.
	 * 
	 * @return int
	 */
	public function getInitialByteSize() {
		return 1;
	}
}
